The present invention relates to novel purine derivatives which possess diuretic, renal protecting, bronchodilatory, antiallergic and hypotensive effects.
As condensed purine derivatives which are structurally analogous to the presently claimed compounds, a compound represented by formula (A) and having a slight bronchodilatory effect is disclosed in J. Med. Chem., 23, 1188 (1980): ##STR2##
Compounds represented by formula (B) are disclosed in Liebigs. Ann. Chem., 11, 1872 (1979): ##STR3## where Q is NH or O.